Determining a person's age (in years) would involve measurement on a(n) scale of measurement.

Explanation:

The levels of measurement include: Nominal, ordinal, interval and ratio.

Nominal is used for classifications, like gender, nationalities or language.

Ordinal is used for comparisons, it has some rank order.

Interval is to express a degree of difference.

Ratio is magnitude, amount of something, and zero doesn't have a specific meaning.

the answer is true when observing or determining population size, a direct observation is use, in which each organism is counted in a population or in an area. one benefit of this measure is that you get the exact population count but it will take a long time to  determine  the  size  of a  population.